Irritable Bowel Syndrome (IBS) is a widespread, chronic, disorder of the lower gastrointestinal tract which seems relatively refractory to standard medical care. Recent research from our laboratory strongly suggests that cognitive therapy (CT) is highly effective (70-80 percent clinically improved) in the short-term (out to 3 months post-treatment). The current application seeks to replicate and extend our previous small-scale studies by conducting a controlled clinical trial of CT vs. a self-help support group as an attention placebo control and symptoms monitoring wait list of 240 chronic IBS patients and follow up the treated patients for at least 12 months. To complete the project in a timely fashion a second site, University of Buffalo Medical Scholl, will be added to run half of the sample. Within this overall project 5 studies will be conducted: (a) examination of relations between stress, especially minor stressful events, and IBS symptoms; (b) controlled comparison of brief (10 sessions) CT administered in small groups to (SG) and to (sic) symptom monitoring. The latter will subsequently be treated to increase the sample sizes for studies c, d, and e; (c) identification of the processes of change within the CT treatment of IBS by examining, at various levels of analysis, the relations between changes in cognitive variables and changes in GI symptoms; (d) prospective one-year follow-up of the effect of CT and SG on IBS; (e) prediction algorithm for the results of the CT treatment of IBS from variables derived from the careful pretreatment assessment of participants; we will determine prediction schemes of end of treatment and a 3-month follow-up as well as what variables predict maintenance of symptom relief over the 12 month follow-up.